I set up dovecot on two servers with replication enabled. The replication is over a vpn connection. I get massive segfaults from doveadm-server every few minutes.

dmesg: doveadm-server[30030]: segfault at 0 ip 0000557fa16d2e62 sp 00007ffdcaafec50 error 4 in doveadm-server[557fa16a3000+41000] [486397.225636] Code: 40 03 4c 8d 3c c3 48 8d 44 24 18 48 89 44 24 08 0f 1f 84 00 00 00 00 00 49 8b bc 24 60 01 00 00 e8 e3 2a 00 00 48 89 44 24 18 <48> 8b 13 48 8d 35 c4 8d 00 00 48 89 c7 e8 2c 2b 00 00 31 c0 c6 45

mail.err dovecot: doveadm: Fatal: master: service(doveadm): child 29507 killed with signal 11 (core dumps disabled)

I am absolutely unaware of how I can come to the cause of this error. Can anyone give me a hint?

Configuration: # 2.2.13: /etc/dovecot/dovecot.conf # OS: Linux 5.1.14-xen x86_64 Debian 8.11 auth_debug = yes disable_plaintext_auth = no doveadm_password = xxxx doveadm_port = 4711 listen = * mail_access_groups = vmail mail_gid = vmail mail_home = /var/vmail/%d/%n mail_location = maildir:~/mail mail_plugins = " notify replication" mail_uid = vmail managesieve_notify_capability = mailto managesieve_sieve_capability = fileinto reject envelope encoded-character vacation subaddress comparator-i;ascii-numeric relational regex imap4flags copy include variables body enotify environment mailbox date ihave namespace inbox { inbox = yes location = mailbox Drafts { auto = subscribe special_use = \Drafts } mailbox Junk { auto = subscribe special_use = \Junk } mailbox Sent { special_use = \Sent } mailbox Trash { auto = subscribe special_use = \Trash } prefix = } passdb { args = /etc/dovecot/dovecot-ldap.conf.ext driver = ldap } plugin { mail_log_events = delete undelete expunge copy mailbox_delete mailbox_rename mail_log_fields = uid box msgid size mail_replica = tcp:backup-vpn.local:12345 sieve = ~/.dovecot.sieve sieve_after = ~/sieve/after sieve_before = ~/sieve/before sieve_default = /var/vmail/%d/default.sieve sieve_dir = ~/sieve } protocols = " imap sieve pop3" service aggregator { fifo_listener replication-notify-fifo { mode = 0666 user = vmail } unix_listener replication-notify { mode = 0666 user = vmail } } service auth { unix_listener auth-client { group = vmail mode = 0660 user = vmail } unix_listener auth-userdb { mode = 0666 user = vmail } } service config { unix_listener config { user = vmail } } service doveadm { client_limit = 1 idle_kill = 0 inet_listener { address = master-vpn.local port = 12345 } process_limit = 0 process_min_avail = 0 user = vmail } service replicator { client_limit = 0 drop_priv_before_exec = no idle_kill = 4294967295 secs process_limit = 1 process_min_avail = 0 service_count = 0 unix_listener replicator-doveadm { group = vmail mode = 0666 user = dovecot } vsz_limit = 8 G } ssl_cert =